|
| Epilepsy syndrome | Clinical features | EEG features at presentation |
| Age of seizure onset | Seizure types | Underlying etiology | Prognosis | Background | Interictal | Ictal |
|
| Early infantile epileptic encephalopathy (ohtahara syndrome) | First 2 weeks of life | Tonic seizures | Cerebral structural abnormality, genetic abnormalities (i.e., STXBP1) | 25% die by 2 years or evolves to West syndrome and profound disability | Suppression burst pattern in awake and sleep | High voltage (150–350 uV) paroxysm | Generalized paroxysms or focal discharges |
|
| Early myoclonic encephalopathy | First weeks of life | Myoclonic seizures (erratic/fragmentary/
generalized); focal seizures | Metabolic genetic etiologies (nonketotic hyperglycinemia, pyridoxine/pyridoxal-5-phosphate dependency, molybdenum cofactor deficiency, organic aciduria, amino-acidopathies) | 50% die within first year or profound disability | Suppression burst pattern, enhanced by sleep | High voltage (150–350 uV) paroxysm | Generalized paroxysms or focal discharges |
|
| Migrating focal seizures in infancy | 3 months | Focal motor seizures with autonomic manifestations | Unknown;
SCN1A, PLCB1, KCNT1 mutations;
2q24, 16p11.2 copy number variants | High mortality before 1 year or profound disability (cortical visual impairment; acquired microcephaly) | Hemispheric background slowing | Multifocal discharges, maximal in temporal and rolandic regions | Rhythmic, monomorphic alpha or theta discharges in noncontiguous brain regions |
|
| West syndrome | 3–8 months | Epileptic spasms | Heterogenous (congenital cortical malformations, tuberous sclerosis, trisomy 21, trisomy 18, CDKL5, ARX, MECP2) | Depends on etiology; other seizure types evolve by about 5 years | Poorly organized, high amplitude (500–1000 mV), generalized slowing | Multifocal epileptiform discharges with generalized electrodecrement | Generalized sharp wave followed by electrodecrement |
|
| Dravet syndrome | 6 months | Febrile status epilepticus, alternating hemiconvulsions→ absence, and myoclonic seizures | 80% SCN1A mutation | Mortality in childhood 10%, intellectual disability, or crouched gait without spasticity in adults | Normal, generalized or focal slowing | Generalized, multifocal or focal discharges; photoparoxysmal response | Generalized paroxysms or focal discharges |
|
| ESES-related syndromes | 5–8 years | Focal seizures | CSWS structural;
LKS unknown | Relapsing-remitting course or age limiting by teenage years | Normal or focal/diffuse slowing | Focal/multifocal/generalized discharges; marked sleep activation with increased interictal spatial distribution or bilateral synchrony; sleep spike wave index >85%;
CSWS-frontal predominant
LKS-temporal predominant | Focal discharges |
|
| Lennox-Gastaut syndrome | 1–8 years | Multiple (tonic, atonic, absences, myoclonic, or focal) | Heterogenous | Intellectual disability | Normal or generalized slowing | Frequent slow spike waves 1.5–2.5 Hz or multifocal | Absence-low spike and waves; tonic-generalized attenuation with recruiting rhythm;
atonic-generalized polyspike/spike waves, or attenuation;
myoclonic-generalized polyspike/spike waves |
|
| Myoclonic-atonic epilepsy | 7 months–6 years | Multiple (atonic, myoclonic, absences, or rarely tonic) | No consistent etiology | 50% normal cognition at last followup | Normal or mild diffuse/focal slowing | Generalized polyspike-and-wave discharges; photoparoxysmal response | Generalized spike or polyspike-and-wave |
|
| Progressive myoclonic epilepsies | Varies by etiology | Prominent myoclonic seizures | Inborn errors of metabolism and mitochondrial disorders
(Tay-Sachs, Alpers syndrome, Lafora disease, Unverricht-Lundborg disease, or neuronal ceroid lipofuscinosis) | Developmental regression/dementia; mortality depends on etiology | Generalized slowing | Generalized/multifocal discharges; photoparoxysmal response in Unverricht-Lundborg and neuronal ceroid lipofuscinosis
| Generalized discharges |
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